GENUS MYXOSTOMA. Ill 



the teeth rather coarser, strongly compressed, the lower five or six much 

 stronger than the others, which are rapidly diminished in size upwards, 

 each with a prominent internal cusp. 



Scales large, more or less quadrate in form, nearly equal in size over 

 the body, and not specially crowded anywhere, usually about 44 in the 

 lateral line (41 to 5G), and about twelve series between dorsal and ven- 

 trals. Lateral line well developed, straight or anteriorly decurved. 



Fins well developed, the dorsal inserted about midway of the 

 body, its first rays usually rather nearer snout than the caudal, the 

 number of developed rays usually about 13, but varying in different 

 species from 11 to 17 : anal fin short and high, usually emarginate in 

 the male fish, probably always with seven developed rays : ventrals in- 

 serted nearly under the middle of the dorsal; their number of rays nor- 

 mally 9, occasionally varying to 10 ; the occurrence of ten ventral rays 

 is probably an accidental individual character, and not a permanent 

 specific one : caudal fin deeply forked, the lobes about equal, except in 

 two species. 



Air-bladder with three chambers: skeleton essentially as in Gatostomus, 

 the vertebrae in M. carpio 27-14 (Giinther). 



Sexual peculiarities little marked, the males in the spawning season 

 with the lower fins reddened, and the anal rays swollen and somewhat 

 tuberculate. 



This genus is widely diffused, some of its species occurring in all the 

 waters of the United States east of the Rocky Mountains, excepting 

 those of the New England States. Some of the more aberrant species 

 seem to be quite local; other species are of the widest distribution. The 

 principal species in the genus, although not the technical type, M. ma- 

 crolepidotum, is very widely difiused, and is subject to much variation. 



This genus is one readily recognizable by external appearance, its 

 species being known to the fishermen as '■'■Bed Horse -^ and "■ xMnlleV^ ) 

 those of other genera being called rather " Suckers". Its proi)er nomen- 

 clature has, however, been a subject of considerable uncertainty. 



The subgenus Moxostoma was originally proposed by Kafiiies(iue to 

 include 6'. anisurus Raf., with the following diagnosis: — ''liody oblong, 

 compressed; head compressed, eight abdominal rays; dorsal fin com- 

 monly longitudinal ; tail commonly unequally forked." 



The characters here noticed are either common to several genera, 

 or else merely specific, and the use of the generic name must de- 

 pend on our identification of the original typical species. By some 



